Steganography Assignment

Here's my code in three of the six photos. I recommend to download these photos from the link below because blogspot changes something and it's difficult to recover the information.

http://www.mediafire.com/?w26zr0yx6p1z89x

After the deadline, I'm going to explain how my algorithm works.

Happy hack :)

 

Parameters to encrypt:

1.- Name of the text to encrypt
2.- The image to hide the message
3.- The name of the image with the message

Example:

imagenes.py photo8.bmp copia8.bmp

Parameters to decrypt:

1.- Name of the image with the message
2.- The file to put the message
3.- The keyword "decripta"

Example: 

copia6.bmp recuperado6.dat decripta

Código

	#parameters to encrypt
	# name of the text to encrypt, the image and the name of the image with the message
	# example
	# imagenes.py photo8.bmp copia8.bmp
	#
	#parameters to decrypt
	# the name of the image with the message, the file to put the message and the keyword "decripta"
	# example
	# copia6.bmp recuperado6.dat decripta
	import Image
	import binascii
	import numpy as np
	from PIL import ImageDraw
	from sys import argv
	from math import sqrt, ceil
	from random import random
	def receivePlaintext(message):
	bin_message = ''
	aux = ''
	for m in message:
	aux = bin(int(binascii.hexlify(m), 16))[2:]
	while len(aux) < 7:
	aux = '0' + aux
	bin_message += aux
	return bin_message
	def receiveLengthtext(message):
	l_message = bin(int(binascii.hexlify(message), 16))[2:]
	return l_message
	def receiveBinarytext(b):
	s = '%x' % (int('0b' + b, 2))
	while len(s) < 2:
	s = '0' + s
	return binascii.unhexlify(s)
	def positions(w, h, n):
	pixels = list()
	k = int(ceil(sqrt(n)))
	dx = w / (k + 1)
	dy = h / (k + 1)
	for i in xrange(k):
	x = (i + 1) * dx
	for j in xrange(k):
	y = (j + 1) * dy
	pixels.append((x, y))
	return pixels
	def getMessage(image):
	im = Image.open(image)
	message = list()
	width, height = im.size
	im = im.convert('RGB')
	pix = im.load()
	message= ''
	character = ''
	eachNum = ''
	large = ''
	for x in xrange(width):
	r, g, b = pix[x, 1]
	if g % 2 == 0 and b % 2 == 0:
	eachNum+='0'
	print "Encontre 0"
	if g % 2 != 0 and b % 2 != 0:
	eachNum+='1'
	print "Encontre 1"
	if g % 2 == 0 and g % 2 !=0:
	break
	if g % 2 != 0 and g % 2 == 0:
	break
	print large
	large = receiveBinarytext(eachNum)
	print "Largo del mensaje ",large
	large = int(large)
	pos = positions(width, height, large)
	for (x, y) in pos:
	r, g, b = pix[x, y]
	if r % 2 == 0: # 1 para impares y 0 para pares
	character += '0'
	else:
	character += '1'
	print 'Obtuvo con (%d, %d, %d) en (%d, %d) un bit %s' % (r, g, b, x, y, character[-1])
	if len(character) == 7:
	if '1' in character:
	c = receiveBinarytext(character)
	message += c
	character = ''
	return message
	def perturbacion(color, b):
	bit = int(b)
	if bit == (color % 2):
	return color
	#print bit, (color % 2)
	diff = 1
	if random() > 0.5:
	diff *= -1
	color += diff
	#print bit, (color % 2)
	if color > 255:
	color -= 2
	elif color < 0:
	color += 2
	#assert(bit == (color % 2))
	#print 'color %d' % color
	return color
	def setMessage(message, image, copy):
	n = len(message) * 7
	im = Image.open(image)
	width, height = im.size
	print width, height
	im = im.convert('RGB')
	pix = im.load()
	pos = positions(width, height, n)
	bits = receivePlaintext(message)
	while len(bits) < len(pos):
	bits += '0'
	i = 0
	for (x, y) in pos:
	r, g, b = pix[x, y]
	bit = bits[i]
	#print 'Poniendo con (%d, %d, %d) en (%d, %d) un bit %s' % (r, g, b, x, y, bit)
	pix[x, y] = perturbacion(r, bit), g, b
	print 'Queda con (%d, %d, %d) en (%d, %d) un bit %s' % (r, g, b, x, y, bit)
	i += 1
	# for (x, y) in pos:
	# print 'Array tiene %s en (%d, %d)' % (data[y, x], x, y)
	num = receiveLengthtext(str(n))
	print "n ",num
	print "n[0] ",num[0]
	print "len(n)",len(num)
	aux = 0
	for x in xrange(width):
	r, g, b = pix[x, 1]
	if(len(num) > aux):
	print aux
	if num[aux] == '0':
	print "pongo 0*"
	if g % 2 != 0:
	g-=1
	if b % 2 != 0:
	b-=1
	if num[aux] == '1':
	print "pongo 1*"
	if g % 2 == 0:
	g+=1
	if b % 2 == 0:
	b+=1
	else:
	if g % 2 == 0 and b % 2 == 0 :
	print "pongo nada"
	g += 1
	if g % 2 != 0 and b % 2 != 0 :
	print "pongo nada"
	g -= 1
	aux+=1
	pix[x, 1] = r, g, b
	data = np.array(im)
	print data.shape
	im2 = Image.fromarray(data)
	im2.save(copy)
	return n
	def main():
	if argv[3] == 'decripta':
	recover = getMessage(argv[1])
	result = open(argv[2], 'w')
	print >>result, recover.strip()
	result.close()
	return
	else:
	message = open(argv[1], 'r')
	msg = ''.join(message.readlines())
	message.close()
	n = setMessage(msg, argv[2], argv[3])
	print 'Message of length %d hidden.' % n
	return
	print 'o_0'
	return
	main()

view raw steganography.py hosted with ❤ by GitHub

**Note** The three images with message are the number 1, 3 and 5.